我使用以下SQL查询给定表的键（主键和外键）及其描述。我正在使用SQL Server 2005。
SELECT c.name 'Column Name' ,
t.name 'Data type' ,
c.max_length 'Max Length' ,
c.precision ,
c.scale ,
c.is_nullable ,
ISNULL(i.is_primary_key, 0) 'Primary Key' ,
CAST (( SELECT COUNT(*)
FROM ( SELECT cx.object_id
FROM sys.foreign_key_columns fkc
INNER JOIN sys.columns cx ON fkc.parent_column_id = cx.column_id
AND fkc.parent_object_id = cx.object_id
INNER JOIN sys.columns cref ON fkc.referenced_column_id = cref.column_id
AND fkc.referenced_object_id = cref.object_id
WHERE cx.column_id = c.column_id
AND fkc.parent_object_id = OBJECT_ID('[dbo].Cards')
) xxx
) AS BIT) AS 'Foreign Key' ,
( SELECT OBJECT_SCHEMA_NAME(fkc.referenced_object_id)
FROM sys.foreign_key_columns fkc
INNER JOIN sys.columns cy ON fkc.parent_column_id = cy.column_id
AND fkc.parent_object_id = cy.object_id
INNER JOIN sys.columns cref ON fkc.referenced_column_id = cref.column_id
AND fkc.referenced_object_id = cref.object_id
WHERE cy.column_id = c.column_id
AND fkc.parent_object_id = OBJECT_ID('[dbo].Cards')
) 'Schema Name' ,
( SELECT OBJECT_NAME(referenced_object_id)
FROM sys.foreign_key_columns fkc
INNER JOIN sys.columns cy ON fkc.parent_column_id = cy.column_id
AND fkc.parent_object_id = cy.object_id
INNER JOIN sys.columns cref ON fkc.referenced_column_id = cref.column_id
AND fkc.referenced_object_id = cref.object_id
WHERE cy.column_id = c.column_id
AND fkc.parent_object_id = OBJECT_ID('[dbo].Cards')
) 'Referenced table' ,
( SELECT cref.name
FROM sys.foreign_key_columns fkc
INNER JOIN sys.columns cy ON fkc.parent_column_id = cy.column_id
AND fkc.parent_object_id = cy.object_id
INNER JOIN sys.columns cref ON fkc.referenced_column_id = cref.column_id
AND fkc.referenced_object_id = cref.object_id
WHERE cy.column_id = c.column_id
AND fkc.parent_object_id = OBJECT_ID('[dbo].Cards')
) 'Referenced column name' ,
( SELECT sep.value [Description]
FROM sys.extended_properties sep
WHERE OBJECT_ID('[dbo].Cards') = sep.major_id
AND c.column_id = sep.minor_id
) Description FROM sys.columns c
INNER JOIN sys.types t ON c.user_type_id = t.user_type_id
LEFT OUTER JOIN sys.index_columns ic ON ic.object_id = c.object_id
AND ic.column_id = c.column_id
LEFT OUTER JOIN sys.indexes i ON ic.object_id = i.object_id
AND ic.index_id = i.index_id WHERE c.object_id = OBJECT_ID('[dbo].Cards');
该查询适用于所有表，除非该表有两个同一个表的外键。
我得到的错误是
"Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression."
我做错了什么？
答案 0 :(得分：1)
我没有检查你的第二个查询，但问题仍然存在： 返回超过1值的子查询就是这个
( SELECT sep.value [Description]
FROM sys.extended_properties sep
WHERE OBJECT_ID('person.stateProvince') = sep.major_id
AND c.column_id = sep.minor_id
) Description
你应该在where子句中添加附加条件：
and class = 1 -- OBJECT_OR_COLUMN
你的查询不考虑表的多于1个索引，加入c.column_id = sep.minor_id你得到更多的行，因为当类是7（索引）时，minor_id是索引id，而不是列id
答案 1 :(得分：0)
我已经解决了自己的问题。
发布此处以防万一有人偶然发现此问题。
SELECT c.name 'Column Name' ,
t.name 'Data type' ,
c.max_length 'Max Length' ,
c.precision ,
c.scale ,
c.is_nullable ,
ISNULL(i.is_primary_key, 0) 'Primary Key' ,
CAST (( SELECT COUNT(*)
FROM ( SELECT cx.object_id
FROM sys.foreign_key_columns fkc
INNER JOIN sys.columns cx ON fkc.parent_column_id = cx.column_id
AND fkc.parent_object_id = cx.object_id
INNER JOIN sys.columns cref ON fkc.referenced_column_id = cref.column_id
AND fkc.referenced_object_id = cref.object_id
WHERE cx.column_id = c.column_id
AND fkc.parent_object_id = OBJECT_ID('[dbo].Cards')
) xxx
) AS BIT) AS 'Foreign Key' ,
( SELECT TOP 1 OBJECT_SCHEMA_NAME(fkc.referenced_object_id)
FROM sys.foreign_key_columns fkc
INNER JOIN sys.columns cy ON fkc.parent_column_id = cy.column_id
AND fkc.parent_object_id = cy.object_id
INNER JOIN sys.columns cref ON fkc.referenced_column_id = cref.column_id
AND fkc.referenced_object_id = cref.object_id
WHERE cy.column_id = c.column_id
AND fkc.parent_object_id = OBJECT_ID('[dbo].Cards')
) 'Schema Name' ,
( SELECT TOP 1 OBJECT_NAME(referenced_object_id)
FROM sys.foreign_key_columns fkc
INNER JOIN sys.columns cy ON fkc.parent_column_id = cy.column_id
AND fkc.parent_object_id = cy.object_id
INNER JOIN sys.columns cref ON fkc.referenced_column_id = cref.column_id
AND fkc.referenced_object_id = cref.object_id
WHERE cy.column_id = c.column_id
AND fkc.parent_object_id = OBJECT_ID('[dbo].Cards')
) 'Referenced table' ,
( SELECT TOP 1 cref.name
FROM sys.foreign_key_columns fkc
INNER JOIN sys.columns cy ON fkc.parent_column_id = cy.column_id
AND fkc.parent_object_id = cy.object_id
INNER JOIN sys.columns cref ON fkc.referenced_column_id = cref.column_id
AND fkc.referenced_object_id = cref.object_id
WHERE cy.column_id = c.column_id
AND fkc.parent_object_id = OBJECT_ID('[dbo].Cards')
) 'Referenced column name' ,
( SELECT sep.value [Description]
FROM sys.extended_properties sep
WHERE OBJECT_ID('[dbo].Cards') = sep.major_id
AND c.column_id = sep.minor_id
) Description FROM sys.columns c
INNER JOIN sys.types t ON c.user_type_id = t.user_type_id
LEFT OUTER JOIN sys.index_columns ic ON ic.object_id = c.object_id
AND ic.column_id = c.column_id
LEFT OUTER JOIN sys.indexes i ON ic.object_id = i.object_id
AND ic.index_id = i.index_id WHERE c.object_id = OBJECT_ID('[dbo].Cards');